Charles Spurgeon Commentary 1 John 2:18-20

"Little children, it is the last hour: and as ye heard that antichrist cometh, even now have there arisen many antichrists; whereby we know that it is the last hour. They went out from us, but they were not of us; for if they had been of us, they would have continued with us: but [they went out], that they might be made manifest that they all are not of us. And ye have an anointing from the Holy One, and ye know all the things." — 1 John 2:18-20 (ASV)

Little children, it is the last time: and as ye have heard that antichrist shall come, even now are there many antichrists; whereby we know that it is the last time. They went out from us but they were not of us; for if they had been of us, they would no doubt have continued with us: but they went out, that they might be made manifest that they were not all of us. But ye have an unction from the Holy One, and ye know all things.

You are taught of God, so you know all that is needful for the attainment of true godliness, and the accomplishment of the divine purpose.